Temperature monitoring is used in many industries. For example, restaurants and food processing companies that rely on refrigeration equipment to keep their products fresh frequently use temperature monitoring. If a malfunction of the refrigeration equipment is not detected promptly, food products could become too hot or too cold, resulting in spoilage or other damage to the food products. For a business that relies on food, such damage could result in a large monetary loss and potentially a serious business disruption.
As another example, companies that manufacture pharmaceutical drugs may monitor temperature of their products. For example, a chemical process on a drug precursor may only succeed in creating a finished product if the process is performed at a particular temperature sustained for a specific amount of time. Any deviations from the process temperature may put the quality of the finished drug at risk. These temperature-sensitive processes require constant and accurate monitoring of temperature to detect variations.
Temperature monitoring systems are known. These systems incorporate temperature sensors attached to or mounted near equipment for which temperature is to be monitored. The system responds if the temperature sensor indicates a temperature outside of a normal operating range. One type of response that has been used is to raise an alarm at a facility where the monitored equipment is located. Some systems use bells, flashing lights or other forms of audible or visible indications of an improper operating temperature.
Because of the sensitivity of some environments, such as pharmaceutical processes, operators of environments that include temperature monitoring systems may use temperature sensors whose performance has been certified according to the certification standards of a standards-setting body, such as the National Institute of Standards and Technology (NIST). Conventional certification processes involve comparing the reading of a test sensor to a reading from a certified reference sensor. The comparison may be performed over several different temperature points. If the difference between the sensor readings is within an acceptable tolerance, the test sensor may be certified. A printed certificate may then be issued that includes identification information for the sensors compared, results of the comparison at the test temperatures, and an expiration date of the certification status. Typically, the certification status expires in one year. After expiration, an operator of an environment may replace the expired sensor with another certified sensor, or recertify the expired sensor. To do so, the operator may request a professional to perform an on-site sensor recertification, return the expired sensor to be recertified and returned to the operator, or purchase a new certified sensor.